Sports Nutrition
IS BASED UPON The basic principles that govern general nutrition That is, a balance of all nutrients, a variety of food and moderation of the intake of that food. With that in mind, the importance of the training diet has been recognised.
THE TRAINING DIET.. Athletes now understand that they must eat well to ensure maximum return from heavy training schedules. The competition diet is established providing athletes with knowledge of special eating practices, before, during and after the event to maximise their performance.
Each sports person will have different dietary requirements depending on Training Age Sex Body size Sport played Factors Environment for training and competition
GENERAL PRINCIPLES OF SPORTS NUTRITION Recommended balanced diet for average sports person is. 55 60% Carbohydrates 25 30% Fats 10 15% Protein Recommended balanced diet for more strenuous athlete is 70% carbohydrates 15 20% Fats 10 15% Protein
GUIDELINES FOR A SPORTS PERSON DIET 1. Increase complex carbohydrates 2. Decrease dietary fat 3. Ensure adequate protein intake 4. Increase dietary fibre 5. Decrease/eliminate alcohol 6. Decrease salt intake 7. Increase water intake
COMPETITION DIET It is important to understand nutritionally related factors that cause fatigue & reduced performance. These being : - depletion of muscle stores dehydration &
STRATEGIES TO REDUCE, DELAY OR OFFSET THESE FACTORS General preparation of energy stores (increase carbohydrate intake to ensure natural storage capacity) Carbohydrate loading for endurance events (gradually reduce training early in the week, maintain normal diet to maintain carb levels reduce training further and consume high level of carbohydrates 80 85% of kj intake) Pre-competition meal (ensure that glycogen stores are topped up for strenuous exercise, adequate hydration)
STRATEGIES CONT.. Carbohydrate supplementation (marathons) (generally in fluid form in small amounts and frequent intervals this maintains blood glucose levels and spares muscle glycogen) Glycogen replenishment (first 15 min after exercise eat foods high in glycogen eg fresh fruit, lollies.. Following two hours meal high in complex carbs & protein Fluid replenishment Before, during and after
CARBOHYDRATES STARCH SUGARS BREADS, CEREALS, RICE, PASTA AND POTATO TABLE SUGAR, HONEY, FRUIT SUGAR, LOLLIES, SOFT DRINK AND BEER
CARBOHYDRATES SIMPLE COMPLEX (contain other useful nutrients) Preferred option for carb intake due to being an efficient energy source, readily used. Stores depleted quickly so need to be replaced frequently Carbohydrates stored as GLYCOGEN in the muscles and liver. Muscles cannot perform without it. Therefore need to be replenished
NUTRIENTS Sources Function Sports of primary use CHO Protein Breads, cereals, rice, pasta, fruit & vegetables Beef, lamb, fish, chicken, eggs The bodies main source of energy to carry out every-day activities Builds and repairs all body cells Team Sports (football, netball etc) Marathon (Long in duration) Fats Water Animal Products meat, chicken etc (saturated) Plants Avocado (unsaturated) Straight from a tap/bottle, fruits (oranges, pears) Supply essential fatty acids that form membrane of cells. Vital in hormone production Transport other nutrients, cells, hormones & wastes around the body Walking, mowing lawns Secondary energy source when CHO s are used All
CHO LOADING Where athletes need high glycogen stores for long-duration events exceeding approximately 90 minutes, carbohydrate loading may be a suitable strategy. CHO loading requires a reduction in the volume of training as well as an increased intake of CHO. CHO loading can be beneficial because increasing CHO stores decreases the reliance on fats, which require more oxygen to break down and are therefore not suitable for high-intensity work. CHO loading theoretically allows high-intensity work to be sustained for longer periods. Examples of when carbohydrate loading may be suitable: Prior to the 40km marathon in the Olympics Prior to an ultra marathon (100km) Prior to a long-distance triathlon
GLYCEMIC INDEX Glycemic Index (GI) ranks carbohydrates according to their effect on blood glucose levels. Low GI foods release glucose slowly, High GI foods release glucose quickly. E.g. Low GI foods include: Wholegrain Breads, Porridge, Brown Rice/Pasta E.g. High GI foods include: Lollies, biscuits, cakes Refer to http://www.oztrack.com/gi.htm for examples of preevent and post event meal plans for athletes.
CARBOHYDRATE GELS Gels consist of sugars and maltodextrins (the same as sports drinks but without the water), which are easily digested. Many gels come with added electrolytes that, as with sports drinks, help maintain fluid balance. Some gels also have added extras such as ginseng and other herbs, amino acids, vitamins, and Co-enzyme-Q10 (a nonessential substance found in the body). How are they used? Most CHO gel packs contain 100 calories or 25 grams of carbohydrate. One to three packets should be consumed for every hour of exercise (depending on intensity and duration).
PROTEIN SUPPLEMETATION Many athletes increase their protein consumption to improve muscle repair and growth. Two forms Isolated proteins sold as protein-only powders (such as whey protein isolate). Proteins mixed with a number of other nutrients to enhance muscle growth such as CHO.
CAFFEINE SUPPLEMENTATION Caffeine is a central nervous system stimulant. Consumed through coffee, tea, energy drinks, chocolate. Not necessary for sports performance. Has a number of effects including: increases heart rate and can affect heart rhythm relaxes smooth muscle (such as intestinal muscles) can produce symptoms of anxiety in high doses decreases an athlete s rating of perceived exertion athletes feel as though they are performing more easily than they actually are.